Components of OS

Operating Systems are complex software systems composed of various components, each responsible for managing different aspects of the computer system. Their architecture defines how these components interact with one another and with hardware and applications.

Process Management

• A process is a running instance of a program.

• OS handles:

  • Process creation, termination
  • Scheduling (deciding which process runs when)
  • Context switching
  • Inter-Process Communication (IPC)
  • Synchronization and deadlock handling

Memory Management

• Tracks each byte of memory in a system: who owns it, how it's used, and how it should be protected.

• Handles:

  • Allocation/deallocation of memory to processes
  • Virtual memory using paging/segmentation
  • Swapping (moving data between RAM and disk)
  • Protection/isolation between processes

File System Management

• Responsible for managing all persistent storage (e.g., SSD, HDD).

• Provides:

  • File and directory structures
  • Access control and permissions
  • Storage abstraction (hide hardware details)
  • File operations (create, read, write, delete)

Device Management

• Manages I/O devices via device drivers.

• Functions include:

  • Buffering, caching, and spooling
  • Providing device-independent interfaces
  • Interrupt handling

I/O System Management

• Bridges the gap between the application and hardware-level I/O operations.

• Uses concepts like:

  • I/O scheduling
  • Drivers
  • User I/O APIs

Security and Protection

• Ensures that unauthorized access is prevented.

• Involves:

  • User authentication
  • Access control lists (ACLs)
  • Isolation of processes
  • Encryption and secure auditing

User Interface

• Enables interaction between users and the system.

• Can be:

  • CLI (Command-Line Interface) — e.g., bash
  • GUI (Graphical User Interface) — e.g., Windows desktop

Networking

• Manages communication between computers via protocols (e.g., TCP/IP).

• Handles:

  • Sockets
  • Protocol stacks
  • Network device drivers

System Calls Interface

• An API through which user programs request services from the OS.
• Acts as the gateway between user space and kernel space.

Summary Table

Component	Role
Process Management	Manages processes, threads, scheduling, IPC
Memory Management	Allocates, protects, and virtualizes memory
File System	Organizes and manages data persistence
Device Management	Manages hardware devices through drivers
Security	Handles access control and isolation
User Interface	Enables user interaction
Networking	Manages communication between computers
System Call Interface	API for apps to request OS services